Shock-absorber for spring motors



Oct. 25, 1955 O. WITTEL SHOCK-ABSORBER FOR SPRING MOTORS Filed Feb. 1, 1952 0 $10 w i it e l INVENTOR.

BYMQWQW class above described.

United States Patent SHOCK-ABSORBER FOR SPRING MOTORS Otto Wittel, Rochester, N. Y., assignor to Eastman Kodak gompany, Rochester, N. Y., a corporation of New ersey Application February 1, 1952, Serial No. 269,547

Claims. 01. 185-45) The present invention relates to a spring motor, and more particularly to a shock-absorbing means for such motors.

As is well known, in motion picture cameras of the amateur type, the film is usually propelled by means of power derived from a wound spring motor. As the motor unwinds, the spring convolutions expand all of which is well known to those in the art. Such motors have certain well-known disadvantages. In order to overcome these disadvantages, there has been developed a new and highly improved type of spring motor in which a pulley has wound thereon a metal coil spring ribbon which is of such a character that the ribbon is normally in equilibrium when wound in spiral form; and is adapted, when unwound, to return automatically to its wound or coiled condition. Opposite ends of the spring ribbon are connected to adjacent spools or pulleys. When the spring ribbon is being wound, it is unwound from one spool, which may be termed the take-up spool, and is then bent or flexed in a direction opposite to its normal coiling, and is then wound on another spool, which may be designated the supply spool. Now, when the filmfeeding mechanism is released, the wound spring will unwind from the supply spool and will rewind back into its original coiled relation on the initial or takeup spool. As the particular form of spring motor is well known and forms no part of the present invention,

further details are not deemed necessary. Such a spring motor is embodied in the Fornelius Patent 2,063,799, issued December 8, 1936, to which reference, may be had.

The inner end of the spring ribbon may be secured to the core of the supply spool in any suitable Orwellknown manner such, for example, as by screws or by a suitable form of a cylindrical clip which is sprung over the end of the spring, or a few inner convolutions thereof. As is well known to those familiar with spring motors of this type, the unwinding is rapid. For this reason it has been found that with prior fastening means the rapid unwinding produced suflicient force at the end of the unwinding to kink and in some cases actually break the spring ribbon adjacent its fastening means on the supply spool, the disadvantages of which are deemed apparent.

In order to overcome these disadvantages, the present invention provides a shock-absorber device which serves to hold or secure the end of the spring ribbon to the supply spool core and which is moved by the spring ribbon near the end of the unwinding operation to ab.- sorb or dampen the unwindingenergy so as to bring the supply spool to a gradual and smooth stop. In addition, no sharp edges are provided about which the spring ribbon may be bent or kinked. The details of this ShOCk-rflbSOl'bfiI will be later described.

The present invention has as its principal object the provision of a shock-absorber for the spring ribbon on the supply spool of a spring motor construction of the 2,721,627 Patented Oct. 25, 1955 Another object of the invention is the provision of a shock-absorber, which is actuated by the ribbon itself during the unwinding, and which serves not only to absorb the unwinding energy of the spring ribbon, but also to prevent undesirable kinking and/or breaking of the ribbon.

Yet another object of the invention is the provision of a shock-absorber device which is simple in construction, easy to apply, inexpensive to manufacture and highly effective in use.

To these and other ends the inventive idea resides in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specification.

In the drawings:

Fig. 1 is a perspective view of a supply spool of a spring motor, with part of one flange broken away, showing the relation thereto of a shock-absorber constructed in accordance with the present invention;

Fig. 2 is a side elevation view of one of the side or end flanges of the spool showing the relation of the apertures therein which cooperate with the shock-absorber to retain the latter in position on the spool core to absorb the unwinding energy so as to eliminate kinking and/or breaking of the spring ribbon.

Fig. 3 is a plan view of the strip from which the shockabsorber is formed;

Fig. 4 is a longitudinal or axial sectional view through the spool core, showing the relation of the part; and

Fig. 5 is a side elevation view of the core illustrated in Fig. 4 showing the slot for receiving the end of the spring ribbon.

Similar reference numerals throughout the various views indicate the same parts.

As mentioned above, the metal coil spring ribbon is wound into a coil on what may be termed the takeup spool. The outer free end 10 of the ribbon 11 is pulled out and positioned in a slot 12 of the core 13 of' the supply spool 14, Fig. 1. The ends of the core or hub 13 are provided with axially extending bosses 15 which extend through registering opening 16 in the end flanges 17 to secure them to the opposite ends of the core 13 in any suitable or well-known manner to provide the complete spool as shown in Fig. 1. The core 13 is formed with an axially extending opening 18- to receive a supporting shaft or spindle 19. The side edges of the core 13 are slightly tapered as shown at 20, Fig. 4, to impart a slight flexing to the flanges 17 to facilitate the free passage of the ribbon 11 between the flanges.

In operation, the supply spool 14, Fig. 1, is rotated in a clockwise direction to unwind spring 11 from the other or take-up spool, not shown, and onto the supply spool 14. During this winding a reverse bend is imparted to the ribbon 11. After the spring ribbon has been wound completely on the supply spool 14 the camera is ready for operation, and the springis wound up in a reversed coiled relation on the spool 14 to provide the motive power for moving the camera parts. For this reason, the spool 14, Fig. 1, may be designated as the supply spool. Suitable releasing means, not shown, is provided to retain the spring in the wound position on the spool 14. When, however, the camera is to be operated, the means is released to free the spools, and the wound spring is then unwound automatically from the supply spool 14 and is rewound in its original coiled condition on the other or take-up spool during the operation of the camera.

It is desirable to attach or anchor the end 10 of the ribbon 11 to the core 13 to prevent disconnection therefrom during the unwinding. However, during this unwinding the ribbon 11 moves rapidly from the supply spool 14 with the result thatiat the-end of the unwinding 3 operation the ribbon is quickly pulled up and stopped with a sudden jerk due to the fact that the end is anchored to the spool 14. This sudden stopping or jerking of the ribbon may tend to kink the latter at its point of anchoring; and, in some cases, may actually break the ribbon, the disadvantages of which are obvious. In order to overcome these disadvantages, the present invention provides the supply spool 14 with a shockabsorber, generally indicated by the numeral 21, Fig. 1, which. serves to absorb the unwinding energy to bring the spool 14 gradually to a stop so as to relieve the ribbon 11 of any sudden jerk or pull at the end of the unwinding.

The shock-absorber 21 of the present invention is formed from a single piece of sheet spring steel which is substantially T-shaped, as shown in Fig. 3, to provide a tailpiece or portion 25 which is bent into a hollow cylindrical form as shown at 26, Fig. 1, to overlie and grip tightly a few inner convolutions 27 of the ribbon 11 to retain the inner end 10 of the ribbon in engagement with the core 13. The portion 25 extends around the core and the inner convolutions 27 for a distance slightly greater than 180, as shown in Fig. 1,- and thus serves to anchor or clip the end 10 securely in the slot 12 of core 13 to prevent disconnection therefrom during the windingoperation. The portion 25 has formed thereon a pair of laterally projecting tongues or ears 28 which register with and extend through apertures 29 in the flanges 17. The apertures 29 are of such size as to receive the ears 28 snugly so as to prevent rotation or other movement of the portion 25 relative to core 13 or the convolutions 27. As the portion 25 is sprung over the convolutions it may be broadly designated as a clip which holds the inner convolutions 27 against the core 13 and retains the end 10 in the slot 12. I

It will be apparent that if the clip portion 25 were terminated adjacent the ears 28, an exposed end edge of the portion would bear on the ribbon convolution immediately below the portion. The result would be that when the end of the unwinding is approached, the end edge would tend to hold a convolution tight against the core while the adjacent section 33 of the ribbon would tend to move rapidly radially. Such relative movement of adjacent sections of the ribbon would cause the ribbon to bend or flex about the end edge of portion 25, and this bending or flexing would tend to bend or kink or possibly break the ribbon at this point.

In order to eliminate such kinking or breaking, the present invention forms the shock-absorber to provide a free cantilever portion 34 which is integral with the clip portion 25, and overlies the free section 33 of the ribbon 11 adjacent the core 13 as clearly illustrated in Fig. 1. It will now be apparent that as the unwinding nears the end, section 33 will move radially and will actually lift the portion 34, as shown in Fig. 1. As the portion 34 so moves it will flex about a line which is substantially in alignment with the ears 28. This line provides, in effect, a hinged connection between the portions 25 and 34 so that the latter may be considered broadly as hingedly or pivotally connected to the portion 25.

The flexible cantilever 34 is formed with a pair of laterally extending ears or lugs 35 which have a length materially greater than the ears 28, as is apparent from an inspection of Figs. 1 and 3. The ears 35 extend through enlarged apertures 36 in the flanges 17. Each aperture 36 is roughly triangular in shape and has an apex 37 which is of small radius, and a curved opposite side 38, the center of which is substantially at a point in alignment with the ears 28 and the apertures 29, the purpose of which arrangement will be later pointed out. The opposite sides 39 and 40 of apertures 36 are arcuate and concave inwardly, as best shown in Fig. 2.

When the ribbon 11 is wound onto spool 14, the outer convolutions of the ribbon press on the upper surface 41 of the portion 34 to move and hold the latter in contact with the inner convolutions 27 In this position, the under surfaces of the ears 35 lie in contact, or substantially in contact, with lower sides 40 of the apertures 36. However, as the end of the unwinding is approached, the outer convolutions wind off the portion 34 and the latter is freed. Further unwinding will then move section 33 toward the position shown in Fig. 1, and such movement will lift portion 34 to cause the latter to pivot or swing about the hinged line which, as mentioned above, is substantially the plane of the ears 28. During such swinging movement, the end 43 of cars 35, which have a length slightly smaller than the radius of the side 38, will move in the apertures 36 adjacent but actually out of contact with the sides 38 so that the cars 35 will move freely in the apertures while the portion 34 is being lifted by the section 33.

Referring now to Figs. 1 and 2, it will be deemed apparent that due to the concave shape of the sides of each aperture 36, when portion 34 is swung outward by section 33, the upper surface 44 of each car 35 will first contact the side 39 of the associated aperture 36 adjacent the apex 37 only. As the lifting or swinging action of the portion 34 continues, the surface 44 will engage progressively along its length with the side 39 in a rolling action. Such progressive rolling engagement of surfaces 44 with the sides 39 serves to absorb or dampen the unwinding energy to bring the spool to a gradual, smooth stop without any jarring or jerking, thus eliminating any tendency to kink or break the ribbon 11. Also, it will be noted that in the stopping action, due to the fact that the portion 34 moves with the ribbon section 33, no sharp edges are presented against which the ribbon may bend or kink. In fact, the end edge 43 of the portion 34 actually moves with section 33 and thus eliminates any fixed or stationary edge on which the ribbon 11 may bend or kink. v

Thus, the section 34, and its associated cars 35, is moved as a unit with the ribbon section 33. Also the ears 35 engage in a gradual and progressive rolling action with the sides 39 to absorb or dampen the energy of the rapidly rotating spool and the moving ribbon during unwinding to bring the parts gradually to a smooth stop, and thus eliminates any sudden jerk or pull on the portion of the ribbon anchored to the core as the end of the unwinding is reached.

From the above description it is apparent that the present invention provides a shock-absorber for use in connection with the spring ribbon of a spring motor. This shock-absorber not only retains the end of the ribbon in attached relation with the supply spool, but also serves to absorb the energy of the rotating spool near the end of the unwinding operation, the advantages of which have been pointed out above. The shock-absorber of the present invention is simple, comprises few parts of rugged construction, inexpensive to manufacture and highly effective in use.

While one embodiment of the invention has been disclosed, it is to be understood that the inventive idea may be carried out in a number of ways. Therefore, the present invention is not to be limited to the precise details described, but is intended to cover all variations and modifications which fall within the scope of the appended claims.

What I claim and desire to secure by Letters Patent of the United States is:

1. The combination with a spool formed with a core and flanges connected to the opposite ends of said core, a ribbon wound in convolutions on said core and having the inner end connected to said core, said ribbon being adapted to be unwound from said core, of a device for absorbing the unwinding shock as the end of the ribbon is approached, said device comprising, in combination, a portion wrapped around inner convolutions of said ribbon to retain the latter on said core, means on said portion cooperating with said flanges to retain said portion in position relative to said core, another portion of said device engaged and moved by said ribbon as the latter nears the end of its unwinding from said core, and cooperating elements on said other portion and said flanges to absorb the unwinding shock at the end of the unwinding.

2. The combination with a spool formed with a core and flanges connected to the opposite ends of said core, a ribbon wound in convolutions on said core and having the inner end connected to said core, said ribbon being adapted to be unwound from said core, of a device for absorbing the unwinding shock as the end of the ribbon is approached, said device comprising, in combination, a portion wrapped around inner convolutions of said ribbon to retain the latter on said core, means on said portion cooperating with said flanges to retain said portion against movement relative to said core, a movable portion adapted to be engaged and moved by said ribbon near the end of the unwinding, and cooperating means on said movable portion and said flanges to absorb the unwinding shock at the end of the unwinding.

3. The combination with a spool formed with a core and flanges connected to the opposite ends of said core, a ribbon wound in convolutions on said core and having the inner end connected to said core, said ribbon being adapted to be unwound from said core, of a device for absorbing the unwinding shock as the end of the ribbon is approached, said device comprising, in combination, a portion wrapped around inner convolutions of said ribbon to retain the latter on said core, means on said portion cooperating with said flanges to retain said portion against movement relative to said core, a movable portion adapted to be engaged and moved by said ribbon near the end of the unwinding, and surfaces on said flanges engaged by said movable portion as the latter is moved by said ribbon to absorb the unwinding shock at the end of the unwinding.

4. The combination with a spool formed with a core and flanges connected to the opposite ends of said core, a ribbon wound in convolutions on said core and having the inner end connected to said core, said ribbon being adapted to be unwound from said core, of a device for absorbing the unwinding shock as the end of the ribbon is approached, said device comprising, in combination, a portion wrapped around inner convolutions of said ribbon to retain the latter on said core, means on said portion cooperating with said flanges to retain said portion against movement relative to said core, a movable portion overlying said ribbon and being movable away from said core by said ribbon as the latter is unwound from said core, and means on said flanges engaged by said movable portion as the latter is moved by said ribbon to absorb the unwinding shock at the end of the unwinding.

5. The combination with a spool formed with a core and flanges connected to the opposite ends of said core, a ribbon wound in convolutions on said core and having the inner end connected to said core, said ribbon being adapted to be unwound from said core, of a device for absorbing the unwinding shock as the end of the ribbon is approached, said device comprising, in combination, a portion wrapped around inner convolutions of said ribbon to retain the latter on said core, means on said portion cooperating with said flanges to retain said portion against movement relative to said core, a flexible cantilever portion integral with said first portion and overlying said ribbon and adapted to be engaged and moved by said ribbon relative to said first portion and said core as said ribbon is unwound, and a surface progressively engaged by said flexible portion as the latter is moved by said ribbon to absorb the unwinding shock at the end of the unwinding.

6. The combination with a spool for-med with a core and flanges connected to the opposite ends of said core,

a ribbon wound in convolutions on said core and having the inner end connected to said core, said ribbon being adapted to be unwound from said core, of a device for absorbing the unwinding shock as the end of the ribbon is approached, said device comprising, in combination, a portion wrapped around inner convolutions of said ribbon to retain the latter on said core, means on said portion cooperating with said flanges to retain said portion against movement relative to said core, a flexible cantilever portion integral with said first portion and overlying said ribbon and adapted to be engaged and moved by said ribbon relative to said first portion and said core as said ribbon is unwound, laterally projecting ears on said flexible portion, said flanges having apertures formed therein to receive said ears, and surfaces on said apertures engaged by said ears as the flexible portion is moved by said ribbon to absorb unwinding shock at the end of the unwinding.

7. The combination with a spool formed with a core and flanges connected to the opposite ends of said core, a ribbon wound in convolutions on said core and having the inner end connected to said core, said ribbon being adapted to be unwound from said core, of a device for absorbing the unwinding shock as the end of the ribbon is approached, said device comprising, in combination, a portion wrapped around inner convolutions of said ribbon to retain the latter on said core, means on said portion cooperating with said flanges to retain said portion against movement relative to said core, a flexible cantilever portion integral with said first portion and overlying said ribbon and adapted to be engaged and moved by said ribbon relative to said first portion and said core as said ribbon is unwound, ears projecting laterally from the opposite sides of said flexible portion, said flanges having enlarged apertures to receive said ears and in which said ears move freely when said flexible portion is moved by said ribbon, and a surface on each aperture engageable by the ear positioned therein to absorb progressively unwinding shock at the end of the unwinding.

8. The combination with a spool formed with a core and flanges connected to the opposite ends of said core, a ribbon wound in convolutions on said core and having the inner end connected to said core, said ribbon being adapted to be unwound from said core, of a device for absorbing the unwinding shock as the end of the ribbon is approached, said device comprising, in combination, a portion wrapped around inner convolutions of said ribbon to retain the latter on said core, means on said portion cooperating with said flanges to retain said portion against movement relative to said core, a flexible cantilever portion integral with said first portion and overlying said ribbon and adapted to be engaged and moved by said ribbon relative to said first portion and said core as said ribbon is unwound, ears projecting laterally from the opposite sides of said flexible portion, said flanges having enlarged apertures to receive said ears and in which said ears move freely when said flexible portion is moved by said ribbon, and an edge of each aperture positioned in the path of a surface of the ear movable therein to engage the ear progressively as the flexible portion is moved by said ribbon to absorb any unwinding shock at the end of the unwinding.

9. The combination with a spool formed with a core and flanges connected to the opposite ends of said core, a ribbon wound in convolutions on said core and having the inner end connected to said core, said ribbon being adapted to be unwound from said core, of a device for absorbing the unwinding shock as the end of the ribbon is approached, said device comprising, in combination, a portion wrapped around inner convolutions of said ribbon to retain the latter on said core, means on said portion cooperating with said flanges to retain said portion against movement relative to said core, a flexible cantilever portion integral with said first portion and overlying said ribbon and adapted to be engaged and moved by said ribbon relative to said first portion and said core as said ribbon is unwound, ears projecting laterally from the opposite sides of said flexible portion, said flanges having enlarged apertures to receive said ears and in which said ears move freely when said flexible portion is moved by said ribbon, and an arcuate edge on each aperture positioned in the path of the upper surface of the ear movable therein and engaged progressively by said surface as said flexible portion is moved by said ribbon to absorb unwinding shock at the end of the unwinding.

10. The combination with a spool formed with a core and flanges connected to the opposite ends of said core, a ribbon wound in convolutions on said core and having the inner end connected to said core, said ribbon being adapted to be unwound from said core, of a device for absorbing the unwinding shock as the end of the ribbon is approached, said device comprising, in combination, a strip of metal formed to provide a partial cylindrical portion overlying a few of the inner convolutions of said ribbon on said core, ears projecting laterally from said portion, said flanges being formed with apertures adapted to receive said ears snugly to hold said portion against movement relative to said core, a flexible cantilever portion integral with and extending from one end of said first portion and overlying a section of said ribbon adjacent said core and adapted to be engaged and moved radially by said section near the end of the unwinding of the ribbon, laterally extending ears formed on said second portion, said flanges having enlarged apertures formed therein adapted to receive said second ears and in which said second ears move when said flexible portion is moved by said section, and a surface on each of said second apertures positioned in the path of the second ear movable therein and engaged progressively by the second ear as said flexible portion is moved by said section to absorb unwinding shock at the end of the unwinding.

References Cited in the file of this patent UNITED STATES PATENTS 

